How your old photos were taken is the first clue to when they were taken. Use our timeline of photographic methods to date and preserve images from your family’s past.

Open a box of family photographs and all types of pictures spill out: paper prints, cased images, tintypes, Polaroids, snapshots. Knowing when each type of photo was produced is one of the first steps in estimating when a picture was taken—a huge clue to who’s in those mystery pictures. A photo’s format also dictates the best ways to save it for posterity. Gather genealogy clues and preserve your family’s past by following our guide to historical photo formats.

Daguerreotypes: 1839 to mid-1860s

Characteristics: A daguerreotype is a copper plate coated with highly polished silver; chemicals including mercury vapor were used to develop the image. Early cameras produced reversed images, but later improvements created true pictures. In order to add realism to the black-and-white image, photo studios employed artists to add color, such as gold jewelry and pink cheeks and lips.